Pat the tuna steaks dry with paper towels. In a shallow dish combine 3 tbsp soy sauce, 1 tbsp grated fresh ginger, 1 tsp minced garlic and 1 tsp sesame oil. Place the tuna in the marinade, turn to coat, and let rest at room temperature for 10 minutes (no longer than 20 minutes to preserve texture).

Season and coat

Mix sesame seeds on a plate. Remove tuna from marinade and season all exposed surfaces lightly with 1 tsp kosher salt and 1 tsp black pepper. Press each steak into the sesame seeds so they adhere and form an even crust on the exterior.

Sear the tuna

Heat a heavy skillet or cast-iron pan over high heat until shimmering. Add 1 tbsp vegetable oil and swirl to coat. Carefully place tuna in the pan and sear 45–60 seconds per side for rare (internal temperature about 115–120°F / 46–49°C). For medium-rare sear 75–90 seconds per side. Avoid overcooking — tuna should remain pink in the center. Remove to a cutting board and let rest 3–4 minutes before slicing thinly on the bias.

Salad greens & vegetables

While the tuna rests, arrange 6 cups mixed salad greens in a large bowl or divide between plates. Add 1 cup thinly sliced cucumber, 1 cup thinly sliced red bell pepper, 2 tbsp sliced scallions and 4 sliced radishes. If using, add 1 sliced avocado just before serving to prevent browning.

Toss gently to combine the vegetables with the greens so dressing will coat evenly later.

Ginger-sesame dressing

Make the dressing

In a small bowl or jar combine 3 tbsp rice vinegar, 1 tbsp mirin, 1 tsp sesame oil, 3 tbsp neutral oil, 1 tsp finely grated ginger, 1 tsp honey, 1 tbsp soy sauce and 1 tbsp fresh lime juice. Whisk or shake vigorously until emulsified. Season with 1/4 tsp salt and 1/4 tsp black pepper to taste. Taste and adjust acidity or sweetness as desired.

Dress the salad

Right before serving, drizzle about half of the dressing over the greens and vegetables (reserve remaining dressing to serve on the side). Toss gently to coat evenly.

Assembly & garnish

Place the dressed greens on serving plates or a platter. Fan the seared tuna slices over the top of the salad. Spoon any resting juices from the cutting board sparingly over the tuna for extra flavor.

Scatter 1 tsp toasted sesame seeds and optional 1/2 cup bean sprouts or microgreens over the salad. Serve with lime wedges and remaining dressing on the side.